HT83C51 HIGH TEMPERATURE 83C51 MICROCONTROLLER FEATURES APPLICATIONS GENERAL DESCRIPTION. HTMOS TM High Temperature Products.

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1 HTMOS TM High Temperature Products HIGH TEMPERATURE 83C51 MICROCONTROLLER Preliminary HT83C51 FEATURES HTMOS Specified Over -55 to +225 C 8-bit CPU Optimized For 5 Volt Control Applications Four 8-bit Bidirectional Parallel Ports Three 16-bit Timer/Counters with One Up/Down Timer/Counter and Clock Out Programmable Counter Array with: Capture/Compare Software Timer with Watchdog Capability High Speed Output Pulse Width Modulator Interrupt Structure with Seven Sources and Four Priority Levels Half Duplex Programmable Serial Port with: Framing Error Detection Automatic Address Recognition 64K External Program Memory Address Space Hermetic 40-Pin Ceramic DIP 64K External Data Memory Address Space 256 Bytes Internal Data Memory 8K Byte Mask ROM On-Chip Oscillator MCS-51Compatible Instruction Set APPLICATIONS Down-Hole Oil Well Avionics Turbine Engine Control Industrial Process Control Nuclear Reactor Electric Power Conversion Heavy Duty Internal Combustion Engines GENERAL DESCRIPTION The HT83C51 is a monolithic 8-bit microcontroller that is pin equivalent to the Intel 8XC51FC microcontroller. Fabricated with Honeywell s dielectrically isolated high-temperature (HTMOS ) process, it is designed specifically for severe high-temperature applications such as down-hole oil well, aerospace, turbine engine and industrial control. and a hierarchical interrupt structure. Software selectable idle is included for reduced power. The HT83C51 varies from the standard 83C51FC, in that it supports half-duplex serial communication, and has 8K Bytes of Mask programmable ROM. The device is available in a standard pinout DIP, with optional packages considered. The HT83C51 uses the standard MCS-51 instruction set which is optimized for control applications. Pin-for-pin equivalent to the MCS-51 series product, it is compatible with all known development environments. Key features include the programmable counter array, watch dog timer, enhanced serial port for multi-processor communication These microcontrollers provide guaranteed performance supporting operating frequencies in excess of 16 MHz over the full -55 to +225 C temperature range. Typically, parts will operate up to +300 C for a year, with derated performance. All parts are burned in at 250 C to eliminate infant mortality. Solid State Electronics Center State Highway 55, Plymouth, MN (800)

2 Microsequencer Instruction Register RAM Addr. Register HT83C51 FUNCTIONAL BLOCK DIAGRAM P0.0 - P0.7 P2.0 - P2.7 Port O Drivers Port 2 Drivers RAM Port O Latch Port 2 Latch Program ROM B Register ACC TMP2 TMP1 Stack Pointer Program Address Register Buffer ALU PSW TMP3 Special Function Registers, Timers, PCA, Serial Port PC Incrementer Program Counter PSENn ALE EAn RST Port 1 Latch Port 3 Latch DPTR Osc. Port 1 Drivers Port 3 Drivers XTAL1 XTAL2 P1.0 - P1.7 P3.0 - P3.7 2

3 PIN DESCRIPTIONS VDD: +5V Supply Voltage VSS: Circuit Ground Port 0 (P0.0 - P0.7): Port 0 is an 8-bit bidirectional I/O port. If external Program and/or Data memory are used, port 0 cannot be used for general purpose I/O. During accesses to external Program and Data memory Port 0 is used as the low-order multiplexed address and data bus. In this mode, Port 0 pins use strong internal pullups when emitting 1 s, and are TTL compatible. If external Program and Data memory are not used, Port 0 pins can be used as general purpose I/O. When the Port pins have 1 s written to them in I/O mode, the pins are floating and can be driven as inputs. An external pullup is required to generate logic high output in I/O mode. Port 1 (P1.0 - P1.7): Port 1 is an 8-bit bidirectional I/O port with internal pullups. The output buffers can drive TTL loads. When the Port 1 pins have 1 s written to them, they are pulled high by the internal pullups and can be used as inputs in this state. As inputs, any pins that are externally pulled low will source current because of the pullups. In addition, Port 1 pins have the alternate uses shown in the table below: Port Alternate Function Pin Name P1.0 T2 External clock input to timer/ Clock out P1.1 T2EX Timer/Counter 2 Capture/Reload trigger and direction control P1.2 ECI External count input to PCA P1.3 CEX0 External I/O for PCA capture/compare Module 0 P1.4 CEX1 External I/O for PCA capture/compare Module 1 P1.5 CEX2 External I/O for PCA capture/compare Module 2 P1.6 CEX3 External I/O for PCA capture/compare Module 3 P1.7 CEX4 External I/O for PCA capture/compare Module 4 Port 2 (P2.0 - P2.7): Port 2 is an 8-bit bidirectional I/O port with internal pullups. The output buffers can drive TTL loads. When the Port 2 pins have 1 s written to them, they are pulled high by the internal pullups and can be used as inputs in this state. As inputs, any pins that are externally pulled low will source current because of the pullups. Port 2 is used as the high-order address byte during accesses to external Program Memory and during accesses to external Data Memory that use 16-bit addresses (i.e. It uses strong internal pullups when emitting 1 s in this mode. During accesses to external Data Memory that use 8 bit addresses, Port 2 emits the contents of the P2 SFR. Port 3 (P3.0 - P3.7): Port 3 is an 8-bit bidirectional I/O port with internal pullups. The output buffers can drive TTL loads. When the Port 3 pins have 1 s written to them, they are pulled high by the internal pullups and can be used as inputs in this state. As inputs, any pins that are externally pulled low will source current because of the pullups. In addition, Port 3 pins have the alternate uses shown in the table below: Port Pin Alternate Name Alternate Function P3.0 RXD Serial port input P3.1 TXD Serial port output P3.2 INT0n External interrupt 0 P3.3 INT1n External interrupt 1 P3.4 T0 External clock input for Timer 0 P3.5 T1 External clock input for Timer 1 P3.6 WRn External Data Memory write strobe P3.7 RDn External Data Memory read strobe RST: Reset input. A high on this input for 2 or more oscillator periods while the oscillator is running resets the device. All ports and Special Function Registers will be reset to their default conditions. Internal data memory is undefined after reset. Program execution will begin within 12 oscillator periods (one machine cycle) after the RST signal is brought low. RST contains an internal pulldown resistor to allow implementing power-up reset with only an external capacitor. ALE: Address Latch Enable. The ALE output is a pulse for latching the low byte of the address during accesses to external memory. In normal operation the ALE pulse is output every 6th oscillator cycle and may be used for external timing or clocking. However, during each access to external Data Memory (MOVX instruction), one ALE pulse is skipped. If desired, ALE operation can be disabled by setting bit 0 of SFR 8EH. When this bit is set, ALE is active only during a MOVX instruction. Otherwise, the pin is held low. When ALE is disabled, program execution must be limited to the internal 8K program ROM. PSENn: Program Store Enable. This active low signal is the read strobe to the external program memory. PSENn is activated every 6th oscillator cycle except that 2 PSENn activations are skipped during external data memory accesses. EAn: External Access Enable. The EAn pin must be strapped to VSS for the HT51 to fetch code from external Program Memory locations 0000H to 1FFFH. The EAn pin must be strapped to VDD for internal program execution from memory locations 0000H to 1FFFH. XTAL1: Input to the inverting oscillator amplifier. XTAL2: Output from the inverting oscillator amplifier. 3

4 OSCILLATOR CHARACTERISTICS The input is XTAL1 and the output is XTAL2 for an inverting amplifier which can be used as an on-chip oscillator as shown in Figure 1. Make sure to qualify the crystal or alternate timing source over the temperature range of the intended application. If an external clock source such as the HTOSC is used, XTAL1 should be driven while XTAL2 floats as shown in Figure 2. There are no duty cycle requirements on the external clock signal, but minimum and maximum high and low times must be observed. IDLE MODE C2 C1 For C1 and C2 values, contact crystal manufacturer Figure 1. Oscillator Connections N/C External Oscillator Signal XTAL 2 XTAL 1 Vss XTAL 2 XTAL 1 Vss Figure 2. External Clock Drive Configuration An instruction that sets the PCON.0-bit causes that to be the last instruction executed prior to going into Idle mode. In the Idle mode, the internal clock to the CPU is gated off but not to the Interrupt, Timer, and Serial Port functions. The PCA can be programmed to either pause or continue operating during Idle Mode. The CPU status is completely preserved and all registers maintain their previous values during Idle Mode. The port pins hold the logical values that they had at the time the Idle mode was activated. ALE and PSENn hold at logic high levels. Idle mode can be terminated in two ways. Activation of any enabled interrupt will cause the PCON.0-bit to be cleared by hardware, terminating Idle mode. The interrupt will be serviced, and following the RETI instruction execution, the instruction after the one that caused Idle mode will be executed. Recovery from Idle mode is 3 oscillator periods plus 3 instruction cycles. The other way that Idle mode can be terminated is through a hardware reset, which can be accomplished by holding the RST pin high for 4 clock periods while the clock is running. Exiting Idle mode with a hardware reset will retain the contents of the on-chip RAM but the values in the SFRs will be lost and program execution will begin at address 0. MEMORY The HT51 has a separate address space for Program and Data Memory. Internally the HT51 contains 8 Kbytes of Program Memory and 256 bytes of Data Memory. It can address up to 64 Kbytes of external Data Memory and 64 Kbytes of external Program Memory. There are 8 Kbytes of internal program memory in the HT51. The EAn pin must be tied to Vdd (power) to enable access to internal program memory locations. When the EAn pin is tied to Vdd, program fetches to addresses 0000H to 1FFFH will be made to internal program ROM. Program fetches to addresses 2000H through FFFFH are to external memory. The EAn pin must be tied to Vss (ground) to enable access to external program memory locations 0000H through 1FFFH. The HT51 implements 256 bytes of internal data RAM. The upper 128 bytes of this RAM occupy a parallel address space to the Special Function Registers (SFRs). The CPU determines if the internal access to an address above 7FH is to the upper 128 bytes of RAM or to the SFR space by the addressing mode of the instruction. If direct addressing is used, the access is to the SFR space. If indirect addressing is used, the access is to the internal RAM. Stack operations are indirectly addressed so the upper portion of RAM can be used as stack space. TIMER/COUNTERS The HT51 contains three 16-bit timer/counters. Each of these are made up of two 8-bit registers (THx, TLx where x = 0, 1, or 2). Each of these three can operate in either timer or counter mode. In the timer mode, the TLx register is incremented once every machine cycle (12 oscillator periods). The count rate is 1/12th of the oscillator frequency. In counter mode, the register is incremented when a 1 to 0 transition is detected on the alternate function input corresponding to that timer (Tx where x = 0, 1, or 2). The maximum rate of count in counter mode that the HT51 can detect is 1/24th of the oscillator frequency. 4

5 PCA COUNTER /TIMER The Programmable Counter Array (PCA) contains a single 16-bit counter/timer made up of the CL and CH registers. This timer is used by all 5 capture/compare modules. Its clock input can be programmed to be from one of four sources. These are the oscillator frequency divided by 12, the oscillator frequency divided by 4, Timer 0 overflow, and an external clock input, ECI, on the alternate function of port pin P1.2. SERIAL PORT The serial port has physically separate receive and transmit buffers, automatic address recognition and four modes of operation as shown below. Mode Description Baud Rate 0 8-bit shift register 1/12 times oscillator freq. 1 8-bit UART variable 2 9-bit UART 1/64 or 1/32 times oscillator freq. 3 9-bit UART variable INTERRUPTS There are seven interrupt sources in the HT51. Two are external interrupts (INT0n, INT1n), three are timer interrupts (Timer 0, Timer 1, and Timer2), one is a PCA interrupt, and one is a serial port interrupt as shown below. PCA interrupt enable Timer 2 interrupt enable Serial port interrupt enable Timer 1 interrupt enable External interrupt 1 enable Timer 0 interrupt enable External interrupt 0 enable RESET The reset input is the RST pin. A reset is accomplished by holding the RST pin high for a minimum of 4 clock periods while the clock is running. The CPU generates an internal reset from the external signal. The port pins are driven to the reset state 2 oscillator periods after a valid 1 is detected on the RST pin. will be made immediately after the RST line is brought low, but the data is not brought into the processor. The memory access will be repeated on the next machine cycle and actual processing will begin at that time. INSTRUCTION SET The instruction set for the HT51 is compatible to the Intel MCS-51 instruction set used on the 8XC51FC. AC CHARACTERISTICS The AC characteristics for the HT51 are shown in the following tables. Each of the timing symbols has 5 characters. The first character is always a T (Time). The other characters, depending on their positions, stand for the logical name of a signal or the logical status of that signal. The following is a list of the characters and what they stand for: A: Address Q: OutputData C: Clock R: RDn signal D: Data T: Time H: Logic level HIGH V: Valid I: Instruction W: WRn signal (program memory contents) X: No longer a L: Logic level LOW, or ALE valid logic level P: PSENn Z: Float For example, TAVLL = Time from address valid to ALE low. The characteristics given are over the operating conditions T A = -55 C to +225 C, V DD = 5V ± %, V SS = 0V. The load capacitance on Port 0, ALE and PSENn = 0 pf. Load capacitance for all other outputs = 50 pf. Inputs during AC testing are to be driven at V DD - 0.5V for logic 1 and 0.45 V for logic 0. Timing measurements are to be made at V IH min for logic 1 and V IL max for logic 0. For timing purposes, a port pin is no longer floating when a 0 mv change from load voltage occurs, and begins to float when a 0 mv change from the loaded V OL /V OH level occurs. Timing diagrams are shown to illustrate the signal relationships depicted in the tables. While RST is high, PSENn is pulled high, ALE is pulled low, and the port pins are pulled weakly high. All SFRs are reset to their reset values. The internal Data Memory content is not affected by reset. In addition, if the HT51 is in Idle or Power Down mode prior to activation of RST, the HT51 will be taken out of Idle or Power Down mode by the reset. The processor will begin operation on the second machine cycle after the RST line is brought low. A memory access 5

6 DC CHARACTERISTICS Symbol VIL Parameter Min (1) Under steady state (non-transient conditions, IOL must be limited externally as follows: maximum IOL per port pin ma maximum IOL per 8-bit port port 0 26 ma port 1,2,3 15 ma maximum total IOL for all output pins 71 ma (2) If IOL exceeds the test conditions, VOL may exceed the related specifications. (3) Pins are not guaranteed to sink current greater than the listed test conditions. Max Input Low Voltage VSS V IH Input High Voltage (except XTAL1, RST) 2. 0 VDD+0. 5 V IH1 Input High Voltage (XTAL1, RST) 3.85 VDD+0. 5 V OL Output Low Voltage (1, 2) (Ports 1, 2, and 3) VOL1 VOH O utput Low Voltage(1, 2) (Port 0, ALE, PSENn) Output High Voltage (Port 1, 2, 3, ALE, PSENn) V OH1 Output High Voltage (Port 0) U nit Test Conditions (3) V V 0.3 V IOL = 0 µ A 0.45 V IOL = 1.6 ma 1.0 V IOL = 3.5 ma 0.3 V IOL = 200 µ A 0.45 V IOL = 3.2 ma 1.0 V IOL = 7.0 ma 4.2 V IOH = - µ A 3.8 V IOH = -30 µ A 3.0 V IOH = -60 µ A 4.2 V IOH = -200 µ A 3.8 V IOH = -3.2 ma 3.0 V IOH = -7.0 ma I IL Logical 0 Input Current(Ports 1, 2, and 3) -50 µ A VIN = 0.45 V I LI Input Leakage Current (Port 0) ± µ A 0.45 V < Vin < VDD I TL Logical 1 to 0 Transition Current(Ports 1, 2, and 3) -650 µ A VIN = 2 V RRST CIO IDD RST Pulldown Resistor 225 KW Pin Capacitance Power Supply Current Operating Idle typical pf ma 1 MHz, 25 C 16 MHz 16 MHz ABSOLUTE MAXIMUM RATINGS (1) Input Voltage, VDD to VSS V to 7.0 V Voltage On Any Pin to VSS V to VDD+0.3 V Power Dissipation mw Storage Temperature to +325 C Lead Temperature (attachment, sec) C IOL per Output Pin ma Stresses in excess of those listed above may result in permanent damage. These are stress ratings only, and operation at these levels is not implied. Frequent or extended exposure to absolute maximum conditions may effect device reliability. 6

7 EXTERNAL PROGRAM AND DATA MEMORY CHARATERISTICS Symbol Parameter Min Max Unit TCLCL Clock Period 62.5 ns 1/TCLCL Oscillator Frequency 16 MHz TLHLL ALE Pulse Width 2 TCLCL-40 ns TAVLL Address Valid to ALE Low TCLCL-40 ns TLLAX Address hold after ALE low TCLCL-30 ns TLLIV ALE low to Valid Instruction In 4 TCLCL-0 ns TLLPL ALE Low to PSENn Low TCLCL-30 ns TPLPH PSENn Pulse Width 3 TCLCL-45 ns TPLIV PSENn low to Valid Instruction In 3 TCLCL-5 ns TPXIX Input Instruction hold after PSENn 0 ns TPXIZ Input Instruction Float After PSENn TCLCL-25 ns TAVIV Address to Valid Instruction In 5 TCLCL-5 ns TPLAZ PSENn Low to Address Float ns TRLRH RDn Pulse Width 6 TCLCL-0 ns TWLWH WRn Pulse Width 6 TCLCL-0 ns TRLDV RDn Low to Valid Data In 5 TCLCL-165 ns TRHDX Data Hold After RDn 0 ns TRHDZ Data Float After RDn 2 TCLCL-60 ns TLLDV ALE Low to Valid Data In 8 TCLCL-150 ns TAVDV Address to Valid Data In 9 TCLCL-165 ns TLLWL ALE Low to RDn or WRn Low 3 TCLCL-50 3 TCLCL+50 ns TAVWL Address Valid to WRn Low 4 TCLCL-130 ns TQVWX Data Valid Before WRn TCLCL-50 ns TWHQX Data Hold After WRn TCLCL-50 ns TQVWH Data Valid to WRn High 7 TCLCL-150 ns TRLAZ RDn Low to Address Float 0 ns TWHLH RDn or WRn High to ALE High TCLCL-40 TCLCL+40 ns 7

8 EXTERNAL PROGRAM MEMORY READ CYCLE ALE TLHLL TLLPL TAVLL TLLIV TPLPH PSENn TPLIV TPLAZ TPXIX TPXIZ TLLAX PORT 0 A0 - A7 INSTR IN A0 - A7 TAVIV PORT 2 A8 - A15 A8 - A15 EXTERNAL DATA MEMORY READ CYCLE ALE TLHLL TWHLH PSENn TLLDV TLLWL TRLRH RDn TAVLL TRLDV TLLAX TRLAZ TRHDX TRHDZ PORT 0 A0 - A7 from RI or DPL DATA IN A0 - A7 from PCL INSTR. IN TAVWL TAVDV PORT 2 P2.0 - P2.7 or A8 - A15 from DPH A8 - A15 from PCH EXTERNAL DATA MEMORY WRITE CYCLE ALE TLHLL TWHLH PSENn TLLWL TWLWH WRn TAVLL TQVWX TWHQX TLLAX TQVWH PORT 0 A0 - A7 from RI or DPL DATA OUT A0 - A7 from PCL INSTR. IN TAVWL PORT 2 P2.0 - P2.7 or A8 - A15 from DPH A8 - A15 from PCH 8

9 SERIAL PORT TIMING CHARACTERISTICS SHIFT REGISTER MODE (MODE 0) HT83C51 Symbol Parameter 16 MHz Oscillator Variable Oscillator Min Max Min Max Unit TXLXL Serial Port Clock Period TCLCL ns TQVXH Output Data Setup to Clock Rising Edge 492 TCLCL-133 ns TXHQX Output Data Hold after Clock Rising Edge 8 2 TCLCL-117 ns TXHDX Input Data Hold after Clock Rising Edge 0 0 ns TXHDV Clock Rising Edge to Input Data Valid 492 TCLCL-133 ns SERIAL PORT TIMING WAVEFORMS ALE TXLXL CLOCK TXHQX TQVXH OUTPUT DATA (WRITE TO SBUF) INPUT DATA (CLEAR RI) TXHDX TXHDV SET TI VALID VALID VALID VALID VALID VALID VALID VALID SET RI 9

10 PERFORMANCE CURVES OVER TEMPERATURE Frequency (MHz) Output Voltage (V) µA 7mA Temperature ( C) Temperature (C) Maximum frequency vs. temperature Output drive vs. temperature C C Operating Current (ma) C 225 C Frequency (MHz) Operating current vs. frequency vs. temperature

11 PROGRAMMING THE MASK ROM The HT83C51 has 8K bytes of on-chip mask programmable ROM. The part is usable with or without this memory space personalised. Once the designer s code has been finalized, the ROM information can be transmitted to Honeywell for metal programming of these memory locations. A non-recurring fee is required to personalize the ROM and a quantity purchase commitment fulfilled. DIFFERENCES BETWEEN INTEL 8XC51FC AND HT83C51 There are a few areas in which the HT51 differs from the 8XC51FC. These differences will be covered in this appendix. In this discussion, 8XC51FC will be used generically to refer to all speed grades of the Intel 8XC51FC family, including the 16MHz 8XC51FC Reset The 8XC51FC requires the RST input to be held high for at least 24 oscillator periods to guarantee the reset is completed in the chip. Also, the port pins are reset asynchronously as soon as the RST pin is pulled high. On the HT51, all portions of the chip are reset synchronously when the RST pin has been high during 2 rising edges of the input clock. 5. DC Characteristics VIL min for the 8XC51FC is -0.5V for all inputs except EAn which has a VIL min of 0V. The HT51 has a VIL min for all inputs of Vss-0.3V. 6. Internal Program Memory The 8XC51FC contains 32 Kbytes of internal program ROM (83C51FC) or EPROM (87C51FC). The HT51 contains 8 Kbytes of internal program ROM. 7. Serial Communications There is a chance the part will miss hardware interrupts when performing full-duplex (simultaneous send and receive) communication or when using the capture or compare modes in the Programmable Counter Array (PCA). As a result, the HT83C51 supports half-duplex operation. Full duplex operation is not supported without additional external hardware. Several acceptable work-around procedures have been identified for the problem associated with the PCA. When coming out of reset, the 8XC51FC takes 1 to 2 machine cycles to begin driving ALE and PSENn. The HT51 will begin driving ALE and PSENn 2 oscillator periods after the RST is removed but the access during the first machine cycle after reset is ignored by the processor. The second cycle will repeat the access and processing will begin. PINOUT DIAGRAM (T2) P1.0 1 (T2EX) P Vdd P0.0 (AD0) 2. Power Off Flag (ECI) P1.2 (CEXO) P P0.1 (AD1) P0.2 (AD2) The Power Off Flag in the PCON register has not been implemented in the HT On Circuit Emulation The On Circuit Emulation mode of operation in the 8XC51FC has not been implemented in the HT51. (CEX1) P1.4 (CEX2) P1.5 (CEX3) P1.6 (CEX4) P1.7 RST (RXD) P3.0 (TXD) P HT P0.3 (AD3) P0.4 (AD4) P0.5 (AD5) P0.6 (AD6) P0.7 (AD7) EAn ALE `4. Operating Conditions (INT0n) P3.2 (INT1n) P PSENn P2.7 (A15) The operating voltage range for the 8XC51FC is 5V ± 20%. The operating temperature range is 0 to 70 C. On the HT51, the operating voltage range is 5V ± %. The full speed operating temperature range is -55 to +225 C; typically, parts will operate up to +300 C for a year, with derated performance. (T0) P3.4 (T1) P3.5 (WRn) P3.6 (RDn) P3.7 XTAL2 XTAL1 Vss P2.6 (A14) P2.5 (A13) P2.4 (A12) P2.3 (A11) P2.2 (A) P2.1 (A9) P2.0 (A8) 11

12 40-LEAD PACKAGE DETAIL D C All dimensions in inches Ceramic Body A L Q 1 Kovar Lid [3] Right Reading on Lid E S2 ea A b b2 C D E e ea L Q S1 S (max) ± typ 0.0 ± ± ± ± ± to ± (min) (min) b2 b (width) e (pitch) S1 THERMAL CHARACTERISTICS Assumes static air convection θjc C/W θja C/W ORDERING INFORMATION HT83C51DC D - Indicates package type* D = Standard DIP *For packaging options, call Honeywell C - Indicates screening level B = High Temperature Class B C = Commercial To learn more about Honeywell Solid State Electronics Center, visit our web site at Honeywell reserves the right to make changes to any products or technology herein to improve reliability, function or design. Honeywell does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others Rev. B 4-98 Helping You Control Your World

High Temperature 83C51 Microcontroller HT83C51

High Temperature 83C51 Microcontroller HT83C51 The HT83C51 is a monolithic 8-bit microcontroller that is pin equivalent to the Intel 8XC51FC microcontroller. Fabricated with Honeywell s HTMOS dielectrically